Conventionally, a battery module formed by arranging a plurality of battery cells such as, for instance, a lithium-ion secondary battery is known. In such a battery module, an array of battery cells is sandwiched between restraints such as metal plates, and is restrained under a fixed load. Thereby, a variation in characteristics such as internal resistance in the battery cells is reduced. For example, in a battery pack set forth in Patent Literature 1, a metal band having bent parts at opposite ends thereof is fixed to an end plate, and a battery block is restrained in a laminating direction by the end plate. In this battery module, for the purpose of preventing damage to a restraining member due to swelling of the battery cells, an elastic body such as rubber may be interposed between the array and the end plate of the restraining member.
Harnesses used for voltage detection or the like in the battery cells may be assembled in the battery module. For example, in a battery pack set forth in Patent Literature 2, a connector having voltage detection terminals is held by a holding member, and the holding member is mounted on a battery group. Thereby, the connector may be collectively electrically connected to electrode terminals of these battery cells.